I'm ultra low carb.

I read that if you are not in ketosis sugar in your body suppresses the Gamma T cells in the mucus membranes of your nasal, throat and lung tissues. Conversly, if you are in ketosis they immune response is strengthened and the Gamma T cells active.

I read this in a few sources, but one never knows. I didn't see it in a peer-reviewed scientific journal so it could be OK or not. Since I'm keto anyway, it's worth a try.

I'm from 2-15 carbs per day plus moderate protein and twice as much fat.

I catch a mild cold every 15 or so years (also a corona virus). One day of runny nose, one day of cough and it's over. The last time I got the flu was over 25 years ago, before I went keto.

So for me, it seems to work.

Bob